Life on Earth During the Miocene Epoch

Updated on July 6, 2014

Restoration of Miocene fauna of North America, on a mural made for the US government-owned Smithsonian Museum. | Source

During cycles long anterior to the creation of the human race, and while the surface of the globe was passing from one condition to another, whole races of animals–each group adapted to the physical conditions in which they lived–were successively created and exterminated. — Sir Roderick Impey Murchison

The Miocene Epoch

The word miocene is derived from the Greek words meion (meaning “less”) and kainos (meaning “recent or new”).This epoch was named by geologist Sir Charles Lyell. The name refers to the fact that it has 18% fewer modern sea invertebrates than the Pliocene.The Miocene Epoch was the earliest division of the Neogene Period which occurred million years to 2.6 million years ago. Extending from 23 million to 5.3 million years ago, the Miocene is often divided into:

Early Miocene (23 - 16 mya)

Middle Miocene (16 - 11.6 mya)

Late Miocene (11.6 - 5.3 mya)

In geological terms, the Miocene is often divided into six ages corresponding to the various rock stages discovered. These ages from oldest to youngest are:

Aquitanian

Burdigalian

Langhian,

Serravallian

Tortonian

Messinian

North and South America are rich in Miocene deposits. Rich deposits also occur in southern Europe, India, Mongolia, East Africa and Pakistan. The fossil record in Miocene deposits is rich in both terrestrial and marine organisms. In particular, the record of terrestrial evolution, particularly of mammals, is extensive.

The Miocene Epoch is is notable for its prehistoric life which included representatives of most of today's flora and fauna. During the Miocene, the earth was experiencing a continuation of the trend of long term cooling begun in the Eocene epoch. However, its climate was warmer than the Oligocene which preceeded it as well as the following Pliocene. Because the climate first wamed and then cooled during the Miocene period, it is significant that two major ecosystems first appeared:

kelp forests of the marine ecosystems

grasslands of the terrestrial ecosystems

Geologic time scale covering the Precambrian and Phanerozoic eons with detail down to the epoch. | Source

Six Ages Of The Miocene Epoch

Period

Epoch

Age

Time Period (millions of years)

Neogene

Miocene

Messinian

5.332–7.246

Tortonian

7.246–11.608

Serravallian

11.608–13.65

(Middle Miocene Extinction event during this stage)

Langhian

13.65–15.97

Burdigalian

15.97–20.43

Subdivision of the Neogene Period according to the IUGS, as of July 2009

Life in the Miocene Epoch

During the Miocene, the open vegetation systems including deserts, tundra and grasslands were expanding while forests were becoming smaller.

Studies of spore and pollen samples from this epoch suggest that most modern seed plant families existed by the end of the Miocene.

A warming trend during the middle Miocene followed by a cooling period was likely responsible for the loss of northern tropical ecosystems, the expansion of coniferous forests in the north and the appearance of definite seasons.

These changes triggered the evolution and diversification of modern grasses and sedges.

Fauna Of The Miocene Epoch

A Miocene crab Tumidocarcinus giganteus in the permanent collection of The Children’s Museum of Indiana. | Source

Thylacosmilus was a genus of sabre-toothed metatherian predators that first appeared during the Miocene. | Source

Protypotherium is an extinct genus of mammal native to South America during the Miocene epoch. | Source

Fossilised Palaeobatrachus gigas. | Source

Source

Comparison of Palaeotragus with two species of Climacoceras (in the foreground). | Source

: Man sitting on Carcharodon megalodon jaws. | Source

Hipparion gracile skeleton, a horse of the Miocene. | Source

Land Bridges And The Diversification Of Life In The Miocene Epoch

Diversification of life during the Miocene was accelerated due to the appearance of land bridges. Connection of continents once separated by water allowed animals to migrate to new habitats, thus extending their geographic ranges.

The primary paths of migration were between Africa, North America, and Eurasia.

The Tethys Ocean, now receded, created a land bridge between Africa and Eurasia.

Elephants and apes ventured over this land bridge extending their range into Eurasia.

Rabbits, pigs, saber-toothed cats, and modern rhinos crossed the same bridge from Eurasia into Africa.

Across the Bering land bridge which connected Siberia and Alaska, rhinos and elephants extended their range even further along while horses made their way from North America into Eurasia.

At the end of the Miocene, only a narrow corridor of water separated North from South America allowing some animals to cross such as Ground Sloths which had evolved in the isolation in South America.

Racoons crossed the same narrow waterway, making their way from North to South America.

The island continent, Australia, gains immigrant species from southeast Asia, including rodents which may have travelled along the Malaysian island chain in order to expand their range.

It does not appear that the migration of these invading species forced native species to extinction.

Rather, it appears that changing climate and vegetation were the cause of most Miocene extinctions.

The Alcoota Fossil Beds in Australia are notable for the occurrence of well-preserved, rare, Miocene vertebrate fossils

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Comments 9 comments

Wow, what an epic hub. I'm actually in the middle of writing a series of hubs detailing the history of life on Earth. At the moment I'm working on the last hub covering the Cenozoic era.

Its amazing just how much of prehistory gets neglected, apart from the dinosaurs of course. But hopefully this hub will the Miocene some much needed exposure. Will you be doing any hubs covering any other geological periods? I'd love to see them. Voted up and shared.

Larry Fields 4 years ago from Northern California

Good job, Teresa. Voted up.

There's been speculation that the connection of the North and South American continents, which disrupted a major ocean current at the end of the Miocene, was the main cause of the Antarctic and Greenland ice caps. What do you think?

Teresa Coppens 4 years ago from Ontario, Canada Author

JKenny, I had to step back for awhile and absorb your comment. I am extremely honoured at your review of my hub. I have always loved prehistory. It is second only to science as my favourite fields of study. I notice that you too share my passion for this subject. I have created series in the past and I had already considered a second installment. Perhaps I will begin at the beginning so to speak of the geological timetable. Thank you so much reading and commenting. I do greatly appreciate the support!

Teresa Coppens 4 years ago from Ontario, Canada Author

Larry, I believe any changes in the techtonic alignment of the earth's plates will result in climate change. The land bridge between the America's would certainly have an impact. It is a plausible theory and I think one I will have to investigate further perhaps adding to this hub. Thank you for your interest and giving me food for thought!

aviannovice 4 years ago from Stillwater, OK

Wonderful historical info involving plants and animals, which of course, transcends each important era.

Doc Sonic 4 years ago from Cape Cod, Massachusetts

Fascinating stuff. You've really made a lot of information accessible and easy to understand. If you did a series on the entire timeline, that would keep you busy for quite a while! I'd read 'em all, too.

Teresa Coppens 4 years ago from Ontario, Canada Author

Thanks so much Doc. It was a time consuming project but so interesting to research. I have been thinking of a series. Thanks for the support!